In a conventional semiconductor device operated at a temperature of less than 200° C., a semiconductor element using Si (silicon) as a base material and a wiring electrode using Al (aluminum) as a main component are used. However, along with increase in the current capacity which flows to the semiconductor device, the semiconductor device is required to operate at a temperature exceeding 200° C. In order to operate the semiconductor device at a temperature exceeding 200° C., a wide bandgap semiconductor has drawn attention as a base material of a semiconductor element. The wide bandgap semiconductor is a semiconductor having a large bandgap and a large dielectric-breakdown electric field compared with Si and is, for example, SiC (silicon carbide), a nitride, diamond, or the like.
Meanwhile, if the semiconductor device using the wiring electrode containing Al as a main component is operated at a temperature exceeding 200° C., there has been a problem that reliability of the semiconductor device is lowered due to, for example, interactions between Al of the wiring electrode and electrodes of the semiconductor element and shape change of the wiring electrode. Therefore, Cu (copper) has drawn attention as a material of a wiring electrode replacing Al. Herein, the semiconductor element and the wiring electrode are covered with an organic resin film for, for example, taking a measure against static electricity in the atmospheric air; however, Cu is easily reacted with an organic resin of the organic resin film before thermosetting. Therefore, a method of forming an inorganic film on the surface of a wiring electrode containing Cu as a main component in order to prevent the reaction with the organic resin before thermosetting is disclosed (for example, Patent Document 1).